Modlcular simulations of deformation and failue in bodns formed by glassy polymer adhesives

摘要

The mechanicla behavior of glassy polymer obnds is examined withmolecular dynamics simulations.We show tht the intrfacial strength of the bond in mode I(tensile) adn mode II(shear) the roughness of the substrte surfce.Failure occurs at the substrate(interfacial failure)when the interaction is wek,and in the bulk (cohesive failure)when the interaction is strong.The transition from interfacial to cohesive fialure unde rmode I loading is nearly unaffected by roughness,while roughness leads toa dramatic increase in interfacila strength unde rmode II loading,.Stress mixity is another crucial parametr thandetermines whether the polymr fails through sheardeformation or through cavtation and crazing.By varying the geometry of the adhesive bond,we illustrate different limiting behaviors of a rupturing film.